SITAEL AOCS & GNC systems range from Sun Sensors with an accuracy of 0.1° to Earth Sensors that work in the TIR region (7.5-14 μm) and able to provide roll and pitch angles with a foreseen accuracy of 1° @ 8 Hz, from Reaction/Momentum Wheels up to Cold Gas Micropropulsion System based on MEMS microdevice.
The SITAEL Sun Sensor is a low cost attitude determination device suitable both for LEO and GEO orbits. Each Sun Sensor group is capable to estimate the Satellite-to-Sun vector with 1° (up to 0.1° when sunlight is perpendicular to sensor’s surface) of accuracy. The Sun Sensor is a 4-Quadrant Sensor (4-Q) based system, with a wide angle pinhole frontend able to guarantee increased precision, light power, and field of view. On-board a microcontroller acquires the 4-Qs data and applies the correction algorithms in real time
The Earth Sensor design by SITAEL is based on COTS. The core of the entire system is a Thermal Infrared micro-camera based on an uncooled microbolometer sensing device. It is able to acquire the Earth TIR emission in the wavelength interval from 7.5 μm to 14.5 μm which matches the Earth IR emission because of its black body temperature of about 288 K.
SITAEL GPS receiver is designed to perform real-time orbit determination on-board LEO satellites. The unit is based on two COTS front-ends kept in cold redundancy. Each front-end is individually protected against high current absorption events with a dedicated re-triggerable current limiter.
SITAEL Reaction/Momentum Wheel (RMW) is an attitude control device suitable for LEO orbits. Each RMW is capable to store up to 0.4 Nms angular moment and to provide up to 10 mNm control torque in a range between 0 and ±4000 rpm. The RMW structure has been optimized in order to provide high angular momentum storage in a reduced volume envelope (120x100x130 mm) and mass (up to 1.2 kg in the fully equipped version). Its internal components are guaranteed for a standard lifetime of about 2 years that could be extended depending on the operating conditions.